So needless to say, it would be a little bit ridiculous to sit and list all of the different phyla, classes, orders, families, genera, and species. But I can take you through an example of a common species of slime mold, Physarum polycephalum. Domain: Eukarya Slime molds are under the Domain Eukarya because they have membrane-bound organelles, true nuclei, and a plasma membrane.
Kingdom: Protista Slime molds are classified under the Kingdom Protista because, like other protists, they really don't fit in with other kingdoms!
Plasmodia often grow to a diameter of several inches and are frequently brightly colored. Both types ingest solid food particles using a process called phagocytosis see endocytosis. They feed on living microorganisms, such as bacteria and yeasts, as well as decaying vegetation. Before entering the reproductive stage, a plasmodium moves to a drier, better-lit place, such as the top of a log. In the amebalike, or cellular, slime molds, up to , individual cells aggregate and flow together, forming a multicellular mass called a pseudoplasmodium that resembles a slug and crawls about before settling in a location with acceptable warmth and brightness.
In the reproductive stage the plasmodium or pseudoplasmodium is transformed into one or more reproductive structures called fruiting bodies, each consisting of a stalk topped by a spore-producing capsule that resembles the reproductive structures of many fungi. Eventually the cellulose-walled spores are released and dispersed; they germinate in wet places, releasing naked cells. Some cells in the slug contribute to a 2—3-millimeter stalk, drying up and dying in the process.
Cells atop the stalk form an asexual fruiting body that contains haploid spores. The spores are disseminated and can germinate if they land in a moist environment. Protostelids are a group that has received less attention than either the Dictyostelids or plasmodial slime molds, as each of the latter groups contains a model organism used to study a specific system.
Protostelids make simple fruiting bodies, similar to the Dictyostelids, with a stalk and spores at the apex. Ceratiomyxa may not actually be a protostelid, but the small, stalked fruiting bodies formed on the external surface are similar to what would be found in a true protostelid.
Plasmodial slime molds represent a vast diversity of morphologies. In their feeding stage, myxomycetes form one large amoeba called a plasmodium with many nuclei and no cell wall. This plasmodium moves over damp, decaying material looking for bacteria and sometimes fungi to engulf and digest. When it dries out or runs out of food, it begins to make fruiting structures called sporangia sporangium, singular.
Inside these sporangia, the diploid nuclei will undergo meiosis and haploid nuclei will be walled off to make spores for aerial dispersal. Dispersal by spores, heterotrophism, and glycogen as a storage carbohydrate originally classified this group within Kingdom Fungi, but this is the end of the similarities. The spores have cell walls made of cellulose, like plants. When these spores land, they will germinate into haploid cells with two flagella called swarm cells or amoebae that will fuse together to form a diploid plasmodium.
The diversity of sporulating structures, or sporocarps , has led many to fall in love with this group of organisms. The life cycle of plasmodial slime molds is best classified as diplontic: the "multicellular" actually just multinucleate phase is diploid. Haploid cells that germinate from spores amoebae or biflagellate swarm cells do not grow until after they have fused with another haploid cell. In some myxomycetes, amoebae or swarm cells produced from the same parent plasmodium can fuse together to form a new plasmodium.
This is called homothallism homo- meaning same, thallus. In other myxomycetes, these gametes must be from different individuals heterothallism , hetero- meaning other. They are the saprophytic type and feed on dead and decaying organic matter.
The name 'slime' is taken from the gelatinous appearance of macroscopic slime moulds. They form aggregates under any unfavourable conditions, and this is common in acellular or plasmodial slime moulds. Their size varies from some centimetres to various square metres. When there is abundant food, they can live as a single-celled organism, primarily cellular slime moulds.
Slime moulds are classified under the Protista kingdom. They resemble fungi and protozoa as well. In modern taxonomy, the true slime moulds fall under Mycetozoa. They are further classified into various classes. The main classes of slime moulds are given below. Dictyostelium - These are cellular slime moulds. They don't form huge coenocytes. Myxomycetes - True or acellular slime moulds.
They are characterised by plasmodial stage, syncytial multinucleated. Acrasia- Cellular slime moulds are similar to dictyostelids but have eruptive pseudopodia.
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